After a few days, he notices that there are always the same people on the carriage that he uses. Every so often one would call out a number and everyone would laugh.
After a few days of this, he decides to enquire of one of the regulars what this is all about
"Well, my dear boy", a nice gent explains to him. "We've been doing this journey for so many years that we've heard just about every joke ever told. We got so bored with it that we've given all the jokes numbers to save time. So when one of us calls out a number, we know exactly which joke it is and can all laugh at it."
He thanks the man, and the next day decides to have a joke himself.
"97", he says loudly. Silence. No-one laughs.
He tries again: "89". No response.
Puzzled, he thinks to himself that maybe there are less than 89 jokes, but then someone else calls out "116" and everyone laughs.
He finds the same gent who explained things to him last time, and asks whether 97 and 89 aren't good jokes or something.
"Ah, my dear boy", the gent replies,
Spoiler:
